The current invention relates to driving a rotary shaft of large, high torque, low speed machines. Many times these types large industrial machines use hydraulic drive systems in place of standard electric drives because these machines are frequently used in portable adaptations on trailers, or in wet, dirty environments where electric motors are undesirable or where an alternate source of motive power, such as a diesel piston engine exists. Aside from these situations, frequently hydraulic drive systems are desirable over standard electric drive systems because of the added expense of the gear reducers needed to convert the high speed and low torque of a standard electric motor to the low speed and high torque required by the machine.
One of the easiest ways of converting the high speed and low torque of a diesel piston engine to the low speed and high torque required by these machines is through a hydraulic drive system. In the majority of these applications, large displacement, multi cylinder, radial piston hydraulic motors are used to drive the machines. These motors are very complex with many precision, tight tolerance machined parts that make them expensive to purchase and expensive to repair if damaged. Because of the numbers of these many tight tolerance parts involved, these motors can be destroyed in seconds if there are contaminants in the hydraulic fluid. Even though the clearances between parts are very tight (small), because there are so many parts there is a large amount of internal leakage which generates a lot of heat.
Henceforth, a new hydraulic cylinder motor adapted to drive a high torque slow speed rotary shaft would fulfill a long felt need with many different industrial and commercial applications. This new invention utilizes and combines known and new technologies in a unique and novel configuration to overcome the aforementioned problems and accomplish this.